Electrode material, electrode, secondary battery, battery pack, and vehicle

1. An electrode material comprising active material particles, wherein the active material particles comprise:

a niobium-titanium composite oxide having an average composition in which a molar ratio of niobium to titanium (M Nb /M Ti ) is greater than 2; and

at least one element A selected from the group consisting of potassium, iron and phosphorus,

wherein the active material particles comprise the at least one element A at a concentration in a range of 100 ppm to 2000 ppm, and the concentration of the at least one element A represents mass [mg/kg] of the at least one element A contained in the active material particles,

wherein the active material particles have a ratio of D10/D50 to D50/D90 ((D10/D50)/(D50/D90)) which is less than 0.6 in a grain size distribution chart according to a laser diffraction/scattering method.

2. The electrode material according to claim 1 , wherein the niobium-titanium composite oxide comprises at least one crystal phase selected from the group consisting of an Nb 2 TiO 7 phase having a composition in which the molar ratio of niobium to titanium (M Nb /M Ti ) is greater than 2, an Nb 10 Ti 20 O 29 phase, an Nb 14 TiO 37 phase and an Nb 24 TiO 62 phase.

3. The electrode material according to claim 1 ,

wherein the niobium-titanium composite oxide comprises an Nb 2 TiO 7 phase having a composition in which the molar ratio of niobium to titanium (M Nb /M Ti ) is greater than 2,

a diffraction diagram for the niobium-titanium composite oxide obtained by powder X-ray diffraction using a Cu-Kα radiation source has a high-angle side peak P H and a low-angle side peak P L in a range of 2θ=44°±1.0°, and

a ratio (I H /I L ) of a peak intensity I H of the high-angle side peak P H to a peak intensity I L of the low-angle side peak P L is less than 1.

4. The electrode material according to claim 1 ,

wherein the niobium-titanium composite oxide comprises at least one crystal phase selected from the group consisting of an Nb 10 Ti 2 O 29 phase, an Nb 14 TiO 37 phase and an Nb 24 TiO 62 phase,

a diffraction diagram for the niobium-titanium composite oxide obtained by powder X-ray diffraction using a Cu-Kμ radiation source has a high-angle side peak P H and a low-angle side peak P L in a range of 2θ=44°±1.0°, and

a ratio (I H /I L ) of a peak intensity I H of the high-angle side peak P H to a peak intensity I L of the low-angle side peak P L is less than 1.5.

5. The electrode material according to claim 1 , wherein a crystallite diameter of the niobium-titanium composite oxide is in a range of 95 nm to 130 nm.

6. The electrode material according to claim 1 ,

wherein the active material particles have D10 in a range of 0.3 μm to 2.0 μm in the grain size distribution chart obtained by the laser diffraction/scattering method.

7. The electrode material according to claim 1 ,

wherein the active material particles have D90 in a range of 5 μm to 30 μm in the grain size distribution chart obtained by the laser diffraction/scattering method.

8. The electrode material according to claim 1 ,

wherein the active material particles have a ratio of D10 to D50 (D10/D50) in a range of 0.10 to 0.60 and a ratio of D50 to D90 (D50/D90) in a range of 0.20 to 0.50 in the grain size distribution chart obtained by the laser diffraction/scattering method.

9. The electrode material according to claim 1 ,

wherein the niobium-titanium composite oxide comprises at least one compound selected from the group consisting of general formula Nb 2 M2 z Ti 1-z O 7 , general formula Nb 10-x M1 x Ti 2-y M2 y O 29 , general formula Nb 14-x M1 x Ti 1-y M2 y O 37 , and general formula Nb 24-x M1 x Ti 1-y M2 y O 62 , and

the M1 is at least one element selected from the group consisting of Ta, Ti, V, Mo and W; the M2 is at least one element selected from the group consisting of Nb, Ta, Zr, Hf and Sn; the x satisfies 0≤x≤5; the y satisfies 0≤y≤1.0, and the z satisfies 0<z<1.

10. An electrode comprising the electrode material according to claim 1 .

11. The electrode according to claim 10 , wherein the electrode comprises an active material-containing layer comprising the electrode material.

12. A secondary battery comprising:

a positive electrode;

a negative electrode; and

an electrolyte,

wherein the negative electrode is the electrode according to claim 10 .

13. A battery pack comprising the secondary battery according to claim 12 .

14. The battery pack according to claim 13 , further comprising:

an external power distribution terminal; and

a protective circuit.

15. The battery pack according to claim 13 , comprising a plurality of the secondary battery, wherein the secondary batteries are electrically connected in series, in parallel, or in combination of in series and in parallel.

16. A vehicle comprising the battery pack according to claim 13 .

17. The vehicle according to claim 16 , which comprises a mechanism configured to convert kinetic energy of the vehicle into regenerative energy.

18. The electrode material according to claim 1 ,

wherein the at least one element A is present in a higher concentration at a particle interface of the active material particle.

19. The electrode material according to claim 1 ,

wherein the at least one element A comprises potassium.

20. The electrode material according to claim 1 ,

wherein the at least one element A comprises potassium and phosphorus.